1. Technical Field
The present disclosure relates to a lighting apparatus using an LED, and more particularly, to a lighting apparatus capable of reducing total harmonic distortion (THD).
2. Related Art
A lighting apparatus is designed to use a light source which exhibits high light emission efficiency using a small amount of energy, in order to reduce energy consumption. Representative examples of a light source used in the lighting apparatus may include an LED.
The LED is differentiated from other light sources in terms of various aspects such as energy consumption, lifetime, and light quality. However, since the LED is driven by a current, a lighting apparatus using the LED as a light source requires a large number of additional circuits for driving a current.
In order to solve the above-described problem, an AC direct-type lighting apparatus has been developed. The lighting apparatus is configured to convert an AC voltage into a rectified voltage, and drive a current using the rectified voltage such the LED emits light. The rectified voltage indicates a voltage obtained by full-wave rectifying an AC voltage. Since the lighting apparatus directly uses a rectified voltage without using an inductor and a capacitor, the lighting apparatus has a satisfactory power factor.
The lighting apparatus using an LED includes a driver which provides a current path in response to light emission following a change of the rectified voltage, and performs current regulation. The driver may be implemented with one chip including transistors such as FETs for providing a current path and performing current regulation.
The driver of the lighting apparatus using an LED emits light in response to a change of the rectified voltage, and nonlinearly controls a current for light emission.
However, the lighting apparatus using an LED has a problem that THD is high due to the nonlinear change of the current. Therefore, the lighting apparatus using an LED needs to improve power efficiency by reducing the THD.